An existing plasma generating apparatus includes a waveguide propagating an electromagnetic wave therethrough, a 3-stub adjusting plasma impedance, and a plasma generating portion generating plasma, where a discharge tube is provided in the plasma generating portion. When an electromagnetic wave is propagated through the waveguide, the electric field concentrates on the plasma generating portion of the waveguide and plasma is generated therefrom.
Therefore, the waveguide is an important factor when designing a structure capable of effectively causing concentration of the electric field.
The structure of the waveguide has been developed to be gradually decreased in height from the existing rectangular flat structure.
FIG. 1 is an entire schematic diagram illustrating a plasma reactor disclosed in Korean Patent Application Laid-Open No. 10-2008-0033408 (hereinafter, referred to as a related art)
Referring to FIG. 1, the plasma reactor according to the related art has a tapered shape of which the height decreases by a predetermined angle so as to cause concentration of the electric field (the electromagnetic wave) applied from the waveguide, and the rear end of the waveguide is provided with a reactor chamber where plasma is generated with the application of the electric field. The related art discloses the tapered waveguide minimizing the amount of the reflected electromagnetic wave, but there is a problem in that the actual concentration effect of the electric field in the actual chamber generating plasma reduces compared to the rear end of the waveguide.